1. Field of the Invention
This invention relates to apparatus for use in wells penetrating subterranean formations. More particularly, it relates to liners; and packers, straddle patches, seal subs and other combinations of apparatus employing the liners in casing or tubing in an oil well or the like.
2. Description of the Prior Art
As described in U.S. Pat. Nos. 3,712,376, entitled "Conduit Liner for Wellbore and Method and Apparatus for Setting Same," inventors, Harrold D. Owen, Wayne O. Rosenthal and James Douglas young; U.S. Pat. No. 3,746,091, entitled "Conduit Liner for Wellbore," inventors, Harrold D. Owen, Wayne O. Rosenthal and James Douglas Young; U.S. Pat. No. 3,776,307, entitled "Apparatus for Setting a Large Bore Packer in a Well," inventor, James Douglas Young; the prior art is replete with practical and impractical liners, alone or in combinations forming or using packers, seal subs and tubular elements. The descriptive matter of these patents is incorporated by reference.
As a part of the prior art, metal liners have been set by being expanded outwardly into tight frictional engagement with the conduit; such as the casing or tubing. The degree and type of tight frictional engagement depends, of course, on the use, or application, for which the liners are intended. For most applications, the liners are set with a tightness that prevents unwanted movement longitudinally of the conduit. Frequently, the liners are set with both tight frictional and sealing engagement, as will be apparent from a description of specific embodiments hereinafter. The tight frictional engagement provides a finite force that is designed for retaining the liner in place to do its job. Obviously, forces larger than design can be generated that are large enough to move the set liner longitudinally of its conduit.
Liners or plugs have been set in a well by detonation of explosive within enclosed chambers or about mandrels within a conduit; bridge plugs have been set by drawing a mandrel up within an expansible annular body and leaving the mandrel emplaced within the annular body; although blocking the well. Liners have also been set by driving an expanding body upwardly or downwardly into and through an expansible body retained in position in the well by supplemental anchor or support means such as a tubing stop or a string of conduit supported on the bottom of the well. Liners have been set by hydraulically forcing a swaging mandrel or swage means upwardly through corrugated liners held in place by the tubing string. Liners have also been set by jarring by repeated firing of an explosive jar brought to the surface and reloaded between firings and by explosively driving a swage means upwardly or downwardly through a corrugated liner held in place by a frangible member with a second explosive charge within the frangible member to destroy it.
The difficulties with the prior art type liners and packers were delineated in the referenced patents and improved liners, straddle patches, packers and method of setting them were described.
Even with the improved structures described in the referenced patents, there are applications in which it is advantageous to employ a relatively thin walled liner in order to lower the forces required for setting the liner and still have the ability to withstand relatively large pressures and to hold the tight frictional and sealing engagement with the conduit in the well (that was often absent in the thin walled liners of the earlier prior art).
Accordingly, it is an object of this invention to provide method and apparatus to be employed to set one or more liners in a well that obviates the disadvantages of the prior art, has a relatively thin walled liner in the unset position but has a set liner that has sufficient wall thickness and strength to withstand the design pressure and sustain design loads without displacement longitudinally of the well.
It is also an object of this invention to provide improved method and apparatus that effects a set liner in which an interior concentrically disposed portion of the liner is in compression to reinforce the exterior portion of the liner that is in tension for a surprisingly strong set liner that has many applications in which it can be employed.
These and other objects will become apparent from the descriptive matter hereinafter, particularly when taken in conjunction with the drawings.
In accordance with this invention, as will be seen hereinafter, a relatively thin walled, expansible liner having an annular body portion with a swage means positioned adjacent thereto is set in the conduit by driving the swage means concentrically interiorly of the body portion and expanding it radially outwardly into tight frictional and sealing engagement with the casing, or tubing, in the well penetrating the subterranean formations. This invention is widely useful in several combinations employing one or more liners with a tubular element depending from a top liner and having an unusually large bore penetrating longitudinally therethrough.